Which statement is true about daily calibration of pycnometers?

• A. Pycnometers should be calibrated each day of use.
• B. Pycnometers should be calibrated monthly.
• C. Calibration is not necessary for pycnometers.
• D. Only one pycnometer needs calibration on a random day.

Answer: (A)

Daily calibration keeps density measurements accurate because a pycnometer and the balance used with it can drift due to temperature changes, residue buildup, or wear. By calibrating every day you verify the actual volume of the pycnometer and confirm the balance readings with standard references, so the mass and density results you report reflect true values for that day’s conditions. If calibration were done only monthly or skipped, small shifts could go unnoticed and skew specific gravity results, which undermines quality control. It's also important to calibrate each pycnometer you use, not just one chosen unit, since each device can have its own slight differences.